The electronics industry has experienced an ever increasing demand for smaller and faster electronic devices which are simultaneously able to support a greater number of increasingly complex and sophisticated functions. Accordingly, there is a continuing trend in the semiconductor industry to manufacture low-cost, high-performance, and low-power integrated circuits (ICs). Thus far these goals have been achieved in large part by scaling down semiconductor IC dimensions (e.g., minimum feature size) and thereby improving production efficiency and lowering associated costs. However, such scaling has also introduced increased complexity to the semiconductor manufacturing process. Thus, the realization of continued advances in semiconductor ICs and devices calls for similar advances in semiconductor manufacturing processes and technology.
As merely one example, semiconductor lithography processes may be used to optically transfer patterns (e.g., using a photomask or reticle) onto a substrate. For instance, in various lithography processes, a resist film is spin-coated onto a surface of a wafer and is subsequently exposed and developed to form a pattern that can be transferred to the wafer (e.g., by a subsequent etching process). With the continued scaling down of IC dimensions, there has been a demand for a reduction in resist film thickness as well as resist materials offering improved reflectivity control, substrate planarization, adhesion promotion, chemical matching, and protection from contamination. Accordingly, various new resist materials and processes have been developed. For example, some lithography processes may employ a silicon-containing resist over a bottom anti-reflective coating (BARC) layer to reduce resist film thickness. In addition, some lithography processes use a tri-layer stack that includes a resist over a silicon-containing BARC layer over an organic underlayer. However, these approaches present new challenges.
For example, the silicon-containing material used in such processes may form a hardened gel by forming cros slinks therein, for example, when solvents of the silicon-containing material dry out. Moreover, the equipment that handles such material must undergo frequent cleaning processes to avoid becoming clogged or otherwise contaminated, and to avoid defect formation on production wafers processed by such equipment. Thus, existing techniques have not proved entirely satisfactory in all respects.